He said: "The first question when you play Barcelona is: which line, which players, are you going to allow to have time on the ball?

"When I went there with Valencia [in April 2016], we allowed the centre backs more time on the ball but then really pressed hard in the wide areas.

"And, of course, as well as doing everything perfect, you also have to be lucky because Barcelona are always going to create chances. We were that day.

Liverpool's John Arne Riise (C) celebrates with Dirk Kuyt (R) and Alvaro Arbeloa after scoring against Barcelona during the first leg of a last 16 Champions League match (Image: LLUIS GENE/AFP/Getty Images)

"In the middle of the pitch, Barcelona are clearly strong and Liverpool should think about how they will stop Sergio Busquets, Arthur, Ivan Rakitic, Philippe Coutinho.

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Ayestaran however conceded that Barcelona will still be able to pose Klopp's side a threat in wide areas, singling out influential left-back Jordi Alba as a key man.

"A lot of the focus is on Messi but for the front players to be dangerous you have to make the ball arrive at the right time, in the right place, and this is down to those in the middle," he added.

Barcelona's Lionel Messi (Image: JOSE JORDAN/AFP/Getty Images)

"The difficulty is when you close the middle of the park, Jordi Alba, the left-back, is someone who can control the game from wide areas.

"Another issue is how Barcelona are going to approach the game. Liverpool normally play the same against any team in any stadium and I don’t think they will change.

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" Liverpool are a massive team at the moment and are able to win any game with the intensity they show and being so 'vertical' in sending the ball quickly to the front players.

"They are able to create a chance from nothing."

Ayestaran was Benitez's assistant coach for three years between 2004 and 2007 and helped the Reds secure a Champions League triumph in May 2005 before coaching them to an FA Cup victory 12 months later.